A cutting accessory is an implement typically removably attached to a powered surgical handpiece to perform a surgical procedure. One cutting accessory used to perform a surgical procedure is a bur. A bur generally comprises a head formed from rigid material, typically metal, shaped to have a number of flutes. The flutes are formed to define cutting edges. The flutes, including the cutting edges are shaped to cut tissue, such as bone or cartilage. A shaft extends proximally from the head. A proximal end of the shaft often has a feature that facilitates locking the shaft to the powered handpiece. Actuation of the handpiece results in rotation of the bur. During a surgical procedure, the head of the bur is placed against a surgical site where a section of tissue is to be removed. The rotating cutting edges excise tissue away from the surgical site. Burs of various shapes and sizes are used in procedures such as orthopedic surgery, neurological and spinal surgery, ear nose and throat surgery and in other surgical procedures to selectively remove a section of tissue.
Many burs work well for the general purpose of removing tissue. Nevertheless, burs have not proven particularly efficient devices for removing tissue in some procedures. For example, it can sometimes be difficult to employ a bur to remove cartilage around a small joint such as the ankle or wrist. This is because cartilage, in comparison to other types of tissue, contains a large percentage by volume of water. When cartilage is cut from tissue, the water component of the cartilage causes the cartilage to adhere to the cutting device. When the cutting device is a bur, the cartilage tends to adhere to surfaces of the flutes. Tissue also collects in the spaces between the adjacent flutes. This cut tissue effectively becomes a debris mass that is pushed around by the flutes. The presence of this debris mass reduces the ability of the cutting flutes to perform their function, to cut more tissue. Further, the debris mass is inherently pushed against the uncut tissue. This moving matter against stationary matter contact results in frictional heating of the debris and the uncut tissue. This heating can damage tissue not intended for removal.
Given the less than efficient cutting of cartilage with a bur, many practitioners, when performing this type of procedure tend to use surgical instruments other than burs to remove this tissue. These instruments tend to be manually operated instruments such as curettes, rongeurs and osteotomes. These instruments are useful for removing soft tissue like cartilage. Given that they are manually operated they are less efficient to use than powered tools such as burs.